1. Field of the Invention
Embodiments of the present invention relate to a wire grid polarizer and a method of manufacturing the same.
2. Description of the Related Art
A polarizer may convert unpolarized light into polarized light, and may be used in, e.g., optical devices, liquid crystal display (LCD) technology, and so forth. A conventional polarizer may split unpolarized light into two polarized components orthogonal to each other, and may, e.g., absorb and/or reflect an undesired polarized component, while transmitting a desired polarized component.
A conventional polarizer absorbing an undesired polarized component may absorb only about 50% or less of light, thereby transmitting some unpolarized light and causing deteriorated brightness and excessive power consumption. A conventional polarizer reflecting an undesired component may have a low polarized-light separation, thereby triggering low contrast. Joint use of absorbing and reflecting polarizers may increase an overall number of elements in a device, enhance size and weight of the device, and increase manufacturing time and costs.
An attempt has been made to use a wire grid polarizer. The conventional wire grid polarizer may include a plurality of metal wires parallel to one another on a substrate, so a pitch between adjacent wires may be shorter than a wavelength of an incident light. As such, unpolarized light incident on the conventional wire grid polarizer may be split into two polarized light components with respect to a direction of an electric-field thereof. More specifically, a light component having an electric field orthogonal to a longitudinal direction of the metal wires, i.e. TM polarized-light, may be transmitted through the wire grid polarizer, and a light component having an electric-field parallel to the longitudinal direction of the metal wires, i.e., TE polarized-light, may be reflected away from the wire grid polarizer.
Proper functioning of a wire grid polarizer, e.g., in a visible light range, may require high transmittance and extinction ratio, and a structure having metal wires with both high aspect ratio and fine distance therebetween, e.g., a pitch of about 200 nm or less. However, conventional wire grid polarizers having metal wires with a high aspect ratio and fine distance therebetween may be hard to manufacture, and may exhibit low compression and/or extension thresholds, thereby providing mechanically unstable and/or unreliable structures. Attempts to strengthen the metal wires of the conventional wire grid polarizer, while maintaining proper functioning thereof may result in complex and impractical structures requiring difficult manufacturing processes.